The main objective of this research plan is to study several aspects of fluid and electrolyte transport in ocular membranes contributing to the maintenance of normal corneal and lens transparency and ocular pressure. The movement of water and ions across the cornea, lens, and ciliary epithelium depends on two factors: a) the permeability of the membrane determined by the physical and histological structure and b) the driving forces mainly produced by local or distant energy yielding chemical reactions. Although each of these two individual factors have been separately studied in cornea, lens and ciliary body, the way in which they are coupled to produce the resulting translocation of ions, remains poorly understood. Using the formalism of the irreversible thermodynamics, emphasis will be put on the link of metabolism to ionic and water transport. The study of active ionic transport in cornea, lens and ciliary body is fragmentary. Of these three tissues, mainly the cornea and in less degree, the ciliary epithelium, have been studied with the Ussing-type methodology. Furthermore, transport characteristics seem to differ among different species. The long term goal is to fully characterize driving forces, mechanisms and types of ionic translocation in cornea, ciliary body and lens of a given experimental animal.